-- Test Expressions
    --Test Number
        DEF MAIN:nat == 0

    -- Test IF THEN ELSE
        DEF def():bool == IF yes(true) THEN no ELSE maybe FI

    -- fehlende Definitionen
        DEF yes(X:bool):bool == true
        DEF no():bool == true
        DEF maybe():bool == true
        DEF id():bool == true

        -- TODO
        DEF parameterUsed(X:nat):bool == yes(1)
